#include<bits/stdc++.h>
using namespace std;
namespace fastio
{
    const int bufl=1<<20;
    const double base1[16]={1,1e-1,1e-2,1e-3,1e-4,1e-5,1e-6,1e-7,1e-8,1e-9,1e-10,1e-11,1e-12,1e-13,1e-14,1e-15};
    const double base2[16]={1,1e1,1e2,1e3,1e4,1e5,1e6,1e7,1e8,1e9,1e10,1e11,1e12,1e13,1e14,1e15};
    struct IN{
        FILE *IT;char ibuf[bufl],*is=ibuf,*it=ibuf;
        IN(){IT=stdin;}IN(char *a){IT=fopen(a,"r");}
        inline char getChar(){if(is==it){it=(is=ibuf)+fread(ibuf,1,bufl,IT);if(is==it)return EOF;}return *is++;}
        template<typename Temp>inline void getInt(Temp &a){a=0;int b=0,c=getChar();while(c<48||c>57)b^=(c==45),c=getChar();while(c>=48&&c<=57)a=(a<<1)+(a<<3)+c-48,c=getChar();if(b)a=-a;}
        template<typename Temp>inline void getDouble(Temp &a){a=0;int b=0,c=getChar(),d=0;__int128 e=0,f=0;while(c<48||c>57)b^=(c==45),c=getChar();while(c>=48&&c<=57)e=(e<<1)+(e<<3)+c-48,c=getChar();if(c==46){c=getChar();while(c>=48&&c<=57)d++,f=(f<<1)+(f<<3)+c-48,c=getChar();}a=e+base1[d]*f;if(b)a=-a;}
        IN& operator>>(char &a){a=getChar();return *this;}
        IN& operator>>(char *a){do{*a=getChar();}while(*a<=32);while(*a>32)*++a=getChar();*a=0;return *this;}
        IN& operator>>(string &a){char b=getChar();while(b<=32)b=getChar();while(b>32)a+=b,b=getChar();return *this;}
        IN& operator>>(int &a){getInt(a);return *this;}
        IN& operator>>(long long &a){getInt(a);return *this;}
        IN& operator>>(__int128 &a){getInt(a);return *this;}
        IN& operator>>(float &a){getDouble(a);return *this;}
        IN& operator>>(double &a){getDouble(a);return *this;}
        IN& operator>>(long double &a){getDouble(a);return *this;}
    };
    struct OUT{
        FILE *IT;char obuf[bufl],*os=obuf,*ot=obuf+bufl;int Eps;long double Acc;
        OUT(){IT=stdout,Eps=6,Acc=1e-6;}OUT(char *a){IT=fopen(a,"w"),Eps=6,Acc=1e-6;}
        inline void ChangEps(int x=6){Eps=x;}
        inline void flush(){fwrite(obuf,1,os-obuf,IT);os=obuf;}
        inline void putChar(int a){*os++=a;if(os==ot)flush();}
        template<typename Temp>inline void putInt(Temp a){if(a<0){putChar(45);a=-a;}if(a<10){putChar(a+48);return;}putInt(a/10);putChar(a%10+48);}
        template<typename Temp>inline void putLeading(Temp a,int b){if(!b)return;putLeading(a/10,b-1);putChar(a%10+48);}
        template<typename Temp>inline void putDouble(Temp a){if(a<0){putChar(45);a=-a;}__int128 b=a;putInt(b);a-=b;a*=base2[Eps];b=a+Acc;putChar(46);putLeading(b,Eps);}
        OUT& operator<<(char a){putChar(a);return *this;}
        OUT& operator<<(char *a){while(*a>32)putChar(*a++);return *this;}
        OUT& operator<<(string a){for(auto c:a)putChar(c);return *this;}
        OUT& operator<<(int a){putInt(a);return *this;}
        OUT& operator<<(long long a){putInt(a);return *this;}
        OUT& operator<<(__int128 a){putInt(a);return *this;}
        OUT& operator<<(float a){putDouble(a);return *this;}
        OUT& operator<<(double a){putDouble(a);return *this;}
        OUT& operator<<(long double a){putDouble(a);return *this;}
        ~OUT(){flush();}
    };
}
using fastio::IN;
using fastio::OUT;
IN fin;
OUT fout;
const int NN=1e6+4;
int a[NN],p[NN],b[NN*2],maxx[NN*2];
vector<int>w[NN];
char s[NN],str[NN*2]; 
void solve()
{
	int n;
	fin>>n;
	for(int i=1;i<=n;i++)
	{
		fin>>a[i];
		a[i]++;
		p[a[i]]=i;
		w[i].clear();
	}
	for(int i=1;i<=n*2-1;i++)
	{
		fin>>b[i];
		int x=(b[i]+1)/2;
		if(i%2)
		{
			if(i/2+1-x<1||i/2+1+x>n)
				continue;
			w[i/2+1-x].push_back(i/2+1+x);
			w[i/2+1+x].push_back(i/2+1-x);
		}
		else
		{
			if(i/2-x<1||i/2+x+1>n)
				continue;
			w[i/2-x].push_back(i/2+x+1);
			w[i/2+x+1].push_back(i/2-x);
		}
	}
	char now='a';
	memset(s,'\0',sizeof(s));
	p[n+1]=0;
	set<int>st;
	for(int i=1;i<=n;i++)
	{
		if(st.count(a[i])||i!=1&&p[a[i]+1]<p[a[i-1]+1])
		{
			now++;
			st.clear();
		}
		if(now>'z')
		{
			fout<<-1<<'\n';
			return;
		}
		s[a[i]]=now;
		for(int j=0;j<w[a[i]].size();j++)
			st.insert(w[a[i]][j]);
	}
	str[0]='$';
	for(int i=1;i<=n;i++)
		str[i*2-1]='#',str[i*2]=s[i];
	str[n*2+1]='#',str[n*2+2]='@';
	int m=n*2+1,maxp=0;
	for(int i=1;i<=m;i++)
	{
		if(maxp+maxx[maxp]>=i)
			maxx[i]=min(maxp+maxx[maxp]-i,maxx[maxp*2-i]);
		else
			maxx[i]=0;
		while(str[i-maxx[i]-1]==str[i+maxx[i]+1])
			maxx[i]++;
		if(i+maxx[i]>maxp+maxx[maxp])
			maxp=i;
		if(i>=2&&i<m&&maxx[i]!=b[i-1])
		{
			fout<<-1<<'\n';
			return;
		}
	}
	fout<<s+1<<'\n';
}
int main()
{
	freopen("string.in","r",stdin);
	freopen("string.out","w",stdout);
	int t;
	fin>>t;
	while(t--)
		solve();
	return 0;
}
